Intermittently operated vacuum horn



Feb. 21, 1950 H. N. DlMlcK 2,498,256

INTERMITTENTLY OPERATED VACUUM HORN Filed July 24, 1945 2 sheets-'sheet 1 Feb.. 21, 1950 H. N. DlMlcK INTERMITTENTLY OPERATED VACUUM HORN 2 Sheets-Sheet 2 Filed July 24, 1945 :gli

y E N R T T jatentefl Feb. v21, 195.0

UNITED STATES PlgTlEZNTj OFFICE INTERMITTENTLY OPERATED VACUUM HORNl Henry N. D'miek, Portland," oreg'.; assig'nor to' Hyster Company, PortlandgO'iegr, a corporation of `Oregon A' Application July 24, 1945, iSerialfNo. 606,785

5'Claims. 1

`This invention relates'to a novel Y`vaou1iinhorn for'producing an audible Warning signal.

The general 'object of 'the invention' is toprovide-a vacuum horn for'vehicles, and the like, whichl does not employdelicate parts or mechanism'srequiring 'frequent adjustment or replacement,V which lis rugged and reliablev in'operation', and Which lWill produce a' loud warning'fsignal. A'further object is'to'providea horn of the type described 'having' associated 'therewith a simple and inexpensive `mechanism vfor' automatically producing periodic or intermittent operation of the h'orn.

With these and other objects 'in View, the'invent-ion resides in the' construction and arrangement 'of l'parts shov'v'n'in the accompanying draw; ings' illustrating a preferred' embodiment of the invention.

FigureA 1 is ato-p plan Viewv of a' vacuui'nhor'n' embodying the Vprinciples 'of the present invention,A

.Figure 2'is a viewtakenA onv the' line 2i-2bf Figure l, showing the horn' in rear elevation', and

y Figure -3 is yan enlargedy longitudinal 'sectional view;

Figureeis a ldiagram showing the connections between the different components of the 'assembly.

The present horn isv a' Warning device of general 'application that is" intended prii'narilyv for use' onvehicles such as straddle trucks in lumber yards. Thesetrucks' constitute a particu# larlyserious hazard to workmen' handling lumber because the Adriver of the truck is'perch'ed high in the air Wherehis view of immediate'surroundings is obstructed by theload carried under the truck. For the safety' of the kother Workmen it has been found' necessary to' provide such trucks with' a Warning device which operates automatically When the-truck' is in use. The present `horn is operated entirely by a vacuum line connected with the intake Vmanifold of the engine of the truck and is provided with anion` and off valve in the cab of the truck. The operator of the truck can thereby turn the valvev so that the horn'will continue to operate while the truck is in use.

Associated with the horn on a common mounting bracket is a vacuum motor connected with the horn vacuum line andarranged to open and close a' valve periodically'connecting the vacuum line With'` the horn. By means of this unitary mechanism,` an intermittent signal is produced in' which the sounding'iintervals -may be varied byfad'justing the'spe'ed of the' motor. Thus the horn mayautomatically'be blown 'at sufciently frequent intervals adequately to Warn all"vv`rl men in the vicinity Witho'ltcletihg'the a'iiioyi ance of a constant, uninterruptedsound. The presenthorn is also-'obviosly applioabl'e to any installation Where an automatic intermittent Warning is desired If such installation does 'not have a source of vacuum available, a'n'iotor driven vacuum pump., lor lthe like, may be included 'in or Connected YWith the device; I

The nom itse1f .comprises,m general, a'pair of circular, mating housing parts II and`l2 s'e'- cnred together by marginal screws I3 which 'also serve to clamp` a diaphragm lit and"gasketv I5 between the parte. The housing parts II an'dfiZ thereby. forni air chambers IG'a-nd I'I on opposite sides of" the diaphragm. The 'iili'tifllaei"' I "Con-4 tains air under atmospheric pressure atall' times but is protectvely covered by4 a removable inspection plate I8 -whichneed not make an air tight connectionwith the housing 'part I I.' Coiiirnunil calling' With the vehaber' IT iS a lVacuufnlin'e"I9 contilledby a valve plunger 2li in a Valve 2|.' The valve 2i' 'is in Vturn connected'with a fitting 272" establish-ing Communication With a branch pipe 23v`ar`1d a li'e 24 leading to an eri'gne'ntak manifold o'r other source` of vacuum. A' valve 25'in this line is mounted in the truck'cab for" the use @fine driver. V

The housing part' l2 carries a horn tube l`3Il^`in axial alignrnent`-vvith an annular`re'cess 3l and the margin ofthe opening 32 is a raised anni1la'r face 33 adapted'toseat'a reciprocatin'g'disc 34,'

The'di'sc'sliiis fixed @nene end of 'a spindle 35 screwed into a diaphragm bushingk 36 mounted on the'diaphragm i4; andV a nut 31 'on the bus'h-4 ing clamps th'eldiaphragrh ti'gl'itlil between" a' spacerSS 'anda' gasket 39 bearing 'against an' enr lar'g'ed head Mlon the'bushing; The disc 34 may" be adjusted' longitudinally with' respect tothe' I'I causingtl'ie diaphragm I4 and the disc'34 to rn'ove'to the'ri'ght 'under the force of atmospheric pressure 'in 'chamber I 6. Upon' a slight movement of the disc 34 to the right, air will enter the chamber I1 through the opening 32 faster than it can leave by way of the pipes I3 and 24 and the pressure in chamber I1 will rapidly build up, returning the diaphragm and the disc 34 to their original positions shown in Figure 3. The rapid repetition of this cycle produces a musical note in the horn 3D.

A bracket 45 is provided for mounting the horn and the valve 2l. The bracket 45 also carries a post 45 for mounting a pneumatic motor 41 to produce intermittent operation of the horn. In the present embodiment the pneumatic motor 4'! consists of a conventional windshield Wiper vacuum motor secured to the post 46 by means of a clamp 48 and a screw 49. This motor is connected with the vacuum line 24 by means of the pipe 23 and is provided with the usual speed control valve 50 and a shut-off valve 5l. For the present purpose the shut-olf valve El is left permanently on and the speed control valve 50 is adjusted to produce the desired frequency of sounding intervals.

The numeral 52 indicates the oscillating shaft of the motor 41 to which the Windshield wiper arm would ordinarily be attached. In the present arrangement, the shaft 52 carries an arm 53 clamped thereon by means of a clamp screw 54 and carrying a cam roller 55 mounted on a pin 56 in a roller slot in the end of the arm. Mounted in the path of the cam roller 55 and bearing upon the valve plunger 20 is a channel shaped cam follower 60 pivoted at 6l to the valve housing 2|. The motor 41 thereby produces continuous oscillation of the cam arm 53 through an arc of 180 or less to depress the valve plunger 2D and sound the horn on each stroke of the cam, the duration of each sounding interval being determined in part by the speed of oscillation of the motor and in part by the position at which the arm 53 is clamped on the motor shaft. If desired, the motor may be shut off at the valve l when the cam is in a position to hold the valve plunger 28 depressed, to cause the horn to emit a continuous instead of an intermittent sound. The valve 5I also may be closed when the cam is raised as in Figure 3 to prevent mischievous operation of the horn by unauthorized persons.

' Figure 4 shows the connections between the different components of the assembly. When valve 25 is opened, the partial vacuum condition in the engine manifold draws a partial vacuum in the main pipe line 24 and also in the branch line 23. When the horn valve 2| is o-pened, atmospheric air is drawn through horn tube 3U and pipe I9 to vibrate the horn diaphragm in the manner described. When shut-on valve 5l is opened, the partial vacuum condition in line 23 is communicated to the variable speed pneumatic motor 4'! to oscillate the cam arm 53. The valve 5l is preferably a quick opening and quick closing slide valve, so that it may be operated to stop the pneumatic motor 4'! instantly to leave the cam arm 53 in a particular position, Thus the valve plunger 2D may be held depressed so that the horn 30 Will sound with a steady tone instead of an intermittent tone whenever the valve 25 in the cab of the truck is opened.

Valve 58 s preferably a slow acting needle valve to serve as a throttle or speed control valve for the pneumatic motor 41. Thus the valve 58 provides for adjustment of the frequency of the sounding interval, which adjustment is not disturbedby operating either of the manual shut off valves 25 or 5l. It is understood, of course,

that the pneumatic motor 47 operates under atmospheric pressure, exhausting through the pipes 23 and 24 into the engine intake manifold in the manner of the ordinary windshield wiper motor.

Various changes in the construction and arrangement of parts will occur to persons skilled in the art, and all such modifications are included in the invention, the same being limited only by the scope of the appended claims.

Having now described my invention and in what manner the same may be used, What I claim as new and desire to protect by Letters Patent is:

l. In an intermittent vacuum horn, a mounting bracket, a vacuum line connection. mounted on said bracket, a valve mounted on said bracket in communication with said vacuum line connec tion, a vacuum motor producing oscillatory motion mounted on said bracket, a vacuum line from said vacuum connection to said motor, a vacuum line from said valve for connection with said horn, and means operated by said motor to intermittently open and close said valve.

2. In a vacuum horn, a mounting bracket, a valve mounted on said bracket, a vacuum line from said valve for connection with said horn, a plunger for opening andclosing said valve, an oscillating shaft vacuum motor mounted on said bracket, valve means for controlling said motor, a cam driven by said motor, and a lever pivoted on said valve and bearing upon said plunger in the path of said cam to constitute a cam follower for operating said valve in accordance with the movements of the cam.

3. In an intermittent vacuum horn, a mounting bracket, a valve mechanism mounted on said bracket for controlling said horn, a variable speed oscillating shaft vacuum motor mounted on said bracket, means operated by said motor for pcriodically opening and closing said valve, and valve means to vary the speed of said motor to control the sounding interval of said horn.

4. In an intermittent vacuum horn, a valve for controlling the sounding of said horn, a vacuum motor for operating said valve intermittently, means to adjust the speed of said motor to vary the frequency of sounding intervals, an oscillating arm driven by said motor and arranged to open said valve at `each stroke thereof, and means to adjust the position of said arm with respect to said motor and said valve to vary the duration of the sounding intervals.

5. In an intermittent vacuum horn, a valve for controlling the sounding of said horn, a vacuum motor having an oscillating shaft, an arm for actuating said valve intermittently, means for securing said arm on said motor shaft in adjusted position to control the duration of each sounding interval, and means to adjust the speed of said motor vto vary the frequency of sounding intervals.

HENRY N. DIMICK.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,046,164 Fanning Dec. 3, 1912 1,419,435 Woodring June 13, 1922 1,786,214 McCune et al Dec. 23, 1930 .1,888,684 Middleton Nov. 22, 1932 1,943,671 Hewitt et al Jan. 16, 1934 2,038,847 Morrow Apr. 28, 1936 

